Grinding plate



June 7, 1938. D. s. ANTHONY l 2,119,768

GRINDING PLATE l Filed Jan. 13, 1956 Patented June 7, 1938 UNITED sTATEs PATENT OFFICE 3 Claims.

This invention relates to new and useful improvements in grinding plates.

One object of the invention is to provide improved complementary grinding platesparticular- 5 ly adapted for use in grinding material which is fed to the plates from the center thereof and is ejected from the periphery of said plates, the plates being constructed so as to more emciently perform the grinding operation.

An important object of the invention is to provide an annular grinding plate having portions along its inner edge bent out of alignment with the plane of the plate, whereby, when two plates are placed cooperatively together, the bent portions will provide enlarged inlets for the material to be crushed between the plates, whereby a uniform feed and decortication, granulation or pulverization of the material is had.

Another object of the invention is to provide an improved grinding disk having concentric rows of sharpened protuberances such as burrs, serrations or teeth on its working face extending from its inner edge to near its outer marginal portion, said burrs, serrations or teeth being all of the same depth and pitch; and additional rows of smaller burrs, serrations or teeth on said outer marginal portion all being of the same pitch, the protuberances on said outer marginal portion being approximately only one-half the size of the other protuberances, whereby the ner or smaller ones serve to finish the grinding operation, which increases the working capacity of the mill and improves the quality of the product.

A further object of the invention is to provide an improved grinding plate which includes a base member anda supplemental disk arranged to be secured thereto, the disk having the grinding teeth made thereon, whereby, when the teeth become dull and replacement is necessary, said so disk may be removed from the base member and a new disk substituted therefor, instead of replacing the entire grinding element; also, this structure permits making the supplemental grinding disk of thin steel, whereby the teeth 45 formedI thereon may be made suiciently sharp for fine grinding, thereby attaining all the advantages of a steel disk without the increased cost incidental to constructing a thick integral steel plate. A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawing, in

which an example of the invention is shown,

and wherein: l Y

Figure 1 Ais a face view of a supplemental grinding disk or plate constructed in accord-ance withthe invention, l 4

Figure 2 is a transverse, sectional View of the same, taken on the line 2 2 of FigureI 1, v

Figure 3 is a cross-sectional view taken on the line 3 3 of Figure 1, on an enlarged scale,

Figure 4 is a sectional view, showing two cooperatively opposed complementary grinding plates in working registration, f

Figure 5 is a face view of the base member or supporting body plate, and l Figure 6 is a transverse, sectional view, taken on the line 6 6 of Figure 5.

In the drawing, the numeral I0 designates a circular flatdisk which is preferably made of steel, but which may be constructed of .any suitable material. The disk is formed with an axial opening II which extends therethrough. The disk as shown is comparatively thin but may be of any desired thickness. Y A I C A multiplicity of enlarged grinding burrs, or teeth I2, formed on theworking face of the rdisk are arranged in concentric rows which extend from the inner edge thereof at the axial opening II to an annular line I3 near the marginal portion of the disk. Y The teeth are preferably V- shaped in cross-section or pyramidal in form and the pitch of all of the teeth of said group is constantv whereby the majority of said teeth are all of the same size.

Any suitable method may be employed in forming the teeth. However, it has been found desirable to form said teeth by first cutting concentric V-shaped grooves Il of the proper depthl in the face of the disk. After these grooves have been cut, the disk is placed in a planer or milling machine, and V-shaped channels or cuts I2 which cross the concentric grooves are milled. The cross cuts do not extend radially from the center of the disk but are formed in groups B, the cuts of each group being parallel.- The first cut C of each group extends tangentially from an imaginary circle A, shown in dotted lines, which has a diameter smaller than the diameter of the axial opening II. Thus, it is obvious that the concentric grooves and cross-cuts form pyramidal burrs or teeth I2 on the face of the disk.

Extending from the annular line I3 on the periphery of the disk tothe edge thereof, an annular outer group of grinding burrs or teeth I4 are provided. The teeth I4 are also arranged in concentric rows, are V-shaped Vin vcross-section, and are formed in the same way as the teeth I2. However, the teeth of this annular outer group, as is clearly shown in Figures 1 and 4, are smaller than those of the groups of teeth I2, preferably being substantially one-half the size thereof. It is noted that the pitch of the teeth I4 is constant, whereby all of said teeth I4 are of the same size.

From the above, it will be seen that a circular grinding disk having two distinct sets of grinding teethis provided; amultiplicity of enlarged teeth I2 which covers the major portion of the face of the disk, and a group of comparatively.

ne or smaller teeth which are located. annularly at the marginal portion of the disk.

After the teeth or burrs I2 and l4^have been" formed on the disk face, said disk is again placed in a milling machine and aplurality of slots I5 are cut therein. The slots extend tangentially from Athe imaginary circle A, and cut entirely through the disk. As is clearly shown in Figure 1, said slots extend from the inner edge of the disk at the axial opening II to a point beyond the middle of the groups B` of enlarged burrs or teeth I2. It is obvious that the cutting of the slots divides the inner portion of the disk into a plurality of sections D. These sections are then bent so Vthat their inner edges are out of alignment with the plane of the disk. It is noted that as shown the sections are bent at one corner away from the face of the diskso that if the disk were lying horizontal with its teeth uppermost, the sections D are bent downwardly. When so bent, the inner portion of the disk is provided with a plurality of corner curved wings. After the plate is so formed, it is, of course, properly tempered and hardened. K

In completing the grinding plate, a circular base or supporting body Vmember I6 having an axial opening I6 is provided. This member has an upstanding peripheral flange VI'I andan annular internal shoulder I8 just below said ange. The shoulder is comparatively narrow in width and between the inner periphery of the shoulder and the inner edge of the base member, said member is formed .with sector-like recesses I9 the bottoms of which are curved so as to correspond to the curved wings of the disk I0.

The disk I is placed within the supporting member I6 so that the underside of its annular outer marginal portion rests on the internal shoulder I8 with the peripheral flange II encircling the edge of said disk I0. The curved wings of the disk I0 engage in the curved recesses I9 of the supporting body member I6, and the axial opening I I in said disk I0 registers with the opening I6 in the member I6. The disk I0 is provided with a plurality of bolt holes20 which register with threaded openings 2| V'in the member I6, when said disk is located on said member I6. The bolt holes are countersunk so asto receive the heads of machine screws (not shown) which pass through the disk and are screwed into the openings 2I of the member I6 to securely fasten the disk and member together to form the complete grinding plate.

In actual use, two cooperatively opposed plates are provided and are positioned face to face so that the concentric rows of teeth on one plate portions do not enter betweeneach other.

The material to be ground is supplied through the registered axial openings II and I 6 in the usual way and as one cooperatively opposed plate rotates with relation to the other, the material enters between the curved or flared wing portions and is fed from between the wings to between the inter-projected teeth I2 and I4 on the nonslotted annular outer portions of the complementary disks. Due to the curvature or flare of the Wings, it will be seen that an enlarged inlet space is provided, which eliminates all danger of crowding the feed, whereby a smooth and even feed is had.

After the material is introduced between the plates, the group of enlarged teeth I2, which are all of the same size, serve to crush and grind the material. If grain is being ground, the same is hulled by these larger teeth. Since the teeth are allof the same size it is obvious that so long as-the grain is passing therebetween, the grinding action is smooth and even, as there is no choking effect due to a reduction in the size of the teeth.

By the time the material reaches the marginal portion of the disk, where the annular group of smaller teeth I4 is located, it is well ground, and since all the heavy work has been done, this group of smaller teeth merely finishes the work to further grind and reduce or pulverize the material. Since the groups of teeth I4 are all of the same size, there is no retarding or choking of the material passing therebetween just prior to ejection due to a gradual increase in the number of the grinding teeth from the central inlet towards the peripheral outlet.

Thus, it is seenr that each disk has the two groups of teeth, the major inner one with larger teeth all of the same size, and the outer one with smaller teeth all ofthe same size. The inner portion of each disk, as hereinbefore described, may-be flared or curved, so as to provide an increased inlet, but, in some cases, only one of the cooperatively opposed disks may have its wing portions flared, the wing portions of the complementary disk being stra-ight, as shown in Figure 4 of the drawing. It is noted that these initial material-receivingwings have some of the teeth I2 thereon and these teeth aid in feeding the material to the major working space between the disks.

It is pointed out that since the disk I0 is made of thin steel, the advantages appurtenant to steel cutting teeth are had, while the expense of making the entire thickness of the plate of steel is overcome. Also, the teeth are formed on the disk and then said disk is tempered. It is well known that during the tempering operation, the thin disk may warp slightly but by bolting the disk to the base member I6, the disk is straightened out when the bolts are tightened, after the formingV of the teeth and tempering, and at the same time said disk is rigidly fastened in proper position on the body member I6.

It is noted that when the burrs or teeth of the disks become dull it is only necessary to remove the disks I0 from the supporting members I6 and substitute new disks therefor. It being unnecessary to replace the entire device, the operating and maintenance cost is greatly minimized.

It is further pointed out that the disk I0 may be made of a very thin gage metal and pressed into the shape shown in the drawing. In such case, after the teeth are formed on the disk, the disk may be stamped by a die to form the wings. So, too, in such case, the slots I may not be necessary in the forming operation, and, therefore.

4there will be no separate wing portions, but the inner marginal portion of the disk will be unbroken annularly and flared continuously around the central opening I I. Also, instead of each separate wing portion being curved or flared at only one corner, as herein first described, it may be flared throughout its entire width.

What I claim and desire to secure by Letters Patent, is:

vl. A grinding plate including, a disk having a circular axial opening therethrough, pyramidal grinding teeth arranged on the working face of the disk in concentric rows, the disk being slotted on lines tangential to a concentric circular line within the axial opening and extending to a coencentric circular line substantially at or near the middle of the disk body, the portions of the disk between the slots being offset from the plane of the disk body to provide an annular series of curved wings at the inner edge portion of the disk surrounding the axial opening.

2. A grinding plate including, a disk having a circular opening through the center thereof, separate grinding teeth on one face of the disk arranged in concentric rows and coviering the entire surface of the disk, the disk being slotted on lines tangential to a concentric circular line 'within the central'opening of the disk and the portions of the disk between the slots being oil'- set with curvature out of alinement with the plane of the rest of the disk from the side opposite to that on which said teeth are provided. 3. A grinding plate including, a disk having an axial circular opening therethrough, a group of concentric circular rows of teeth of a substantially constant size on the face of the disk and extending from the inner edge of the disk to an annular line near its outer margin, a second group of concentric circular rows of teeth of a substantially constant size extending from the annular line where the irst group terminates to the peripheral edge of the disk, the teeth of the second group being smaller than the teeth of the rst group, and an annular series of wings at the inner edge of the disk, said wings being separated on lines tangential to a circular line within the axial opening of the disk and each wing being offset with curvature out of alinement with the plane of the disk from the side of the disk opposite to that on which said groups of teeth are provided. 4

DAVID S. ANTHONY. 

